The neuropeptide receptor for substance P (NK-1) is widely distributed throughout the mammalian nervous system (especially brain and spinal ganglia), the circulatory system and peripheral tissues (especially the duodenum and jejunum) and are involved in regulating a number of diverse biological processes. The receptor for substance P is a member of the superfamily of G protein-coupled receptors.
The central and peripheral actions of the mammalian tachykinin substance P have been associated with numerous inflammatory conditions including migraine, rheumatoid arthritis, asthma, and inflammatory bowel disease as well as mediation of the emetic reflex and the modulation of central nervous system (CNS) disorders such as Parkinson's disease (Neurosci. Res., 1996, 7, 187-214), anxiety (Can. J. Phys., 1997, 75, 612-621) and depression (Science, 1998, 281, 1640-1645).
Evidence for the usefulness of tachykinin receptor antagonists in pain, headache, especially migraine, Alzheimer's disease, multiple sclerosis, attenuation of morphine withdrawal, cardiovascular changes, edema, such as edema caused by thermal injury, chronic inflammatory diseases such as rheumatoid arthritis, asthma/bronchial hyperreactivity and other respiratory diseases including allergic rhinitis, inflammatory diseases of the gut including ulcerative colitis and Crohn's disease, ocular injury and ocular inflammatory diseases has been reviewed in “Tachykinin Receptor and Tachykinin Receptor Antagonists”, J. Auton. Pharmacol., 13, 23-93, 1993.
Furthermore, Neurokinin 1 receptor antagonists are being developed for the treatment of a number of physiological disorders associated with an excess or imbalance of tachykinin, in particular substance P. Examples of conditions in which substance P has been implicated include disorders of the central nervous system such as anxiety, depression and psychosis (WO 95/16679, WO 95/18124 and WO 95/23798).
The neurokinin-1 receptor antagonists are further useful for the treatment of motion sickness and for treatment induced vomiting.
In addition, in The New England Journal of Medicine, Vol. 340, No. 3, 190‥195, 1999 has been described the reduction of cisplatin-induced emesis by a selective neurokinin-1-receptor antagonist.
The usefulness of neurokinin 1 receptor antagonists for the treatment of certain forms of urinary incontinence is further described in Neuropeptides, 32(1), 1-49, (1998) and Eur. J. Pharmacol., 383(3), 297-303, (1999).
Furthermore, U.S. Pat. No. 5,972,938 describes a method for treating a psychoimmunologic or a psychosomatic disorder by administration of a tachykinin receptor, such as NK-1 receptor antagonist.
Life Sci., (2000), 67(9), 985-1001 describes, that astrocytes express functional receptors to numerous neurotransmitters including substance P, which is an important stimulus for reactive astrocytes in CNS development, infection and injury. In brain tumors malignant glial cells originating from astrocytes are triggered by tachykinins via NK-1 receptors to release soluble mediators and to increase their proliferative rate. Therefore, selective NK-1 receptor antagonists maybe useful as a therapeutic approach to treat malignant gliomas in the treatment of cancer.
In Nature (London) (2000), 405(6783), 180-183 is described that mice with a genetic disruption of NK-1 receptor show a loss of the rewarding properties of morphine. Consequently NK-1 receptor antagonists may be useful in the treatment of withdrawal symptoms of addictive drugs such as opiates and nicotine and reduction of their abuse/craving.
NK1 receptor antagonists have been reported to have also a beneficial effect in the therapy of traumatic brain injury (oral disclosure by Prof. Nimmo at the International Tachykinin Conference 2000 in La Grande Motte, France, Oct. 17-20, 2000 with the title “Neurokinin 1 (NK-1) Receptor Antagonists Improve the Neurological Outcome Following Traumatic Brain Injury” (Authors: A. J. Nimmo, C. J. Bennett, X.Hu, I. Cernak, R. Vink).
Aromatic and heteroaromatic substituted amides are generically described in EP 1035115.